Electrophotographic copying machine and a box-shaped magazine for use in such a machine

ABSTRACT

An electrophotographic copying machine traversed by an original and a copy sheet in synchronism from initially spaced, substantially vertical positions, the sheet being accomodated in a sheet holder. Guide means for the original and processing units for electrostatically charging the copy sheet and exposing it to the image of the original are arranged along mainly vertical, downwardly directed travelling paths for said original and copy sheet, stop members serving to detect an original and a copy sheet in the respective initial position. The machine casing is bipartite, one part being suspendable on a wall and the other part being pivotable relative thereto. Copy sheets may be supplied from a box-shaped magazine, a portion thereof being allowed to protrude from the casing through an opening in the top wall thereof.

[451 May 13, 1975 United States Patent n91 Zeuthen 1 ELECTROPIIOTOGRAPHIC COPYING MACHINE AND A BOX-SHAPED 3,558,224 Murgas et 355/66 X MAGAZINE FOR USE IN SUCH A MACHINE Primary Examiner-Samuel S. Matthews [75] Invemor: g Zeuthen Gemofie Assistant E.\'aminerKenneth C. Hutchison enmar Attorney, Agent, or Firm-Stevens, Davis, Miller &

Mosher [73] Assignee:

Filed:

Rexomi A/S, Copenhagen, Denmark May a, 1973 [57] ABSTRACT An electrophotographic copying machine traversed by [Zl] Appl. No.: 358,325

an original and a copy sheet in synchronism from ini- Foreign ApPlication Priority Data tialiy spaced, substantially vertical positions, the sheet Feb. 10, I970 Denmark 632 being accomodated in a sheet holder. Guide means for the original and processing units for electrostatically charging the copy sheet and exposing it to the image of the original are arranged along mainly vertical, downwardly directed travelling paths for said original and copy sheet, stop members serving to detect an [52] US. Cl.... [SI] Int. [58] Field of Search............................

original and a copy sheet in the respective initial position. The machine casing is bipartite, one part being suspendable on a wall and the other part being pivotable relative thereto. Copy sheets may be supplied References Cited UNITED STATES PATENTS 7/l962 l l/l966 l l/ 1966 l 1/1967 3,044,386 Limberger 3,282,!77 Stanton........

3,286,588 Wick et al.

3,352,218 Ostensen......

4/1969 .Hanson........ .4 355/14 3,469,908 9/1969 Marek et 355 3 R 2 Clams 4 Draw I tit iiiiiti\i\ii iiisiiiiiI\. I'I'llll lllllll J I I l llllllllll I! Pmmggm 1 arms 3, 883 .241

sum 102 3 FAIENTEUHAnmms 3.883.241

SHEEI 38? 3 1 ELECTROPI-IOTOGRAPIIIC COPYING MACHINE AND A BOX-SHAPED MAGAZINE FOR USE IN SUCH A MACHINE This is a continuation, of application Ser. No. 112,565, filed Feb. 4, 1971.

BACKGROUND OF THE INVENTION The development of electrophotographic copying machines has resulted in two main types of such machines, i.e., table-size and floor-type machine. Almost all floor-type machines are suitable for the reproduction from books, bulkier equipment and increasing dimensions, weight and costs resulting therefrom.

As a result of consumers demands on the one hand and reasons of competition on the other hand, electrophotographic copying machines are becoming increasingly more complicated. lf printing material in the form of sheets is used, the machine may be provided with magazines for several sheet sizes. In case of printing material in the form of a roll of paper, the machine may be provided with means for cutting off sheets of paper of different lengths. To avoid the necessity of the user having to press a button each time a copy is to be produced of a certain original, the machine may be provided with an automatical repeating device adjustable to the reproduction ofa predetermined number of copies.

In the development that has taken place, attention has not been drawn to the fact that a need exists for a simple and cheap electrophotographic copying machine usable in places where sufficient space is not available either for known table-size machines nor for floor-type machines.

The present invention relates to an electrophotographic copying machine, in which copying sheets having a photo-sensitive surface are charged, exposed and developed, each sheet traversing the machine in synchronism with an original which is scanned by an optical system, by means of which an image of the original is formed directly on the copying sheet.

Traversing machines of the above-mentioned type are known, in the operation of which a copy sheet is taken by hand from a sheet supply, e.g., an external magazine or a drawer, and is placed on an original document to be copied, said copy sheet and original being then introduced into the machine in a horizontal direction on each side of a separating bar arranged in an insertion opening. The purpose of putting the original and the copy sheet together and introducing them into the machine at the same time is to bring about the synchronism necessary for reproducing the original correctly on the copy sheet. However, in practice it often happens that in order to introduce the original and the copying sheet on each side of the separating bar in the insertion opening, said sheets, being put together, are edged forward so that the introduction thereof begins at a corner, the result being that the copy sheet and the original are drawn obliquely into the machine.

In known traversing machines, in which the original disappears into the machine and is ejected again therefrom after exposure, it might happen that the original jams in the machine, for example, in case it is curled and, at the worst, it might be ruined. In such cases, it will be necessary to open the machine and release the jammed original from the feeding rollers for said original. If reversal of the original inside the machine is to be avoided, in order to eject it through an opening in the end wall of the machine parallel to the insertion opening, the original moving right through the machine, said machine has to be accessible from the front side as well as from the rear side thereof, which might be inexpedient for reasons of operation and demands on space.

The present invention solves the problem of providing an electrophotographic copying machine which is simple and cheap and the operation of which offers considerable advantages.

BRIEF SUMMARY OF THE INVENTION According to the invention an electrophotographic copying machine comprises a casing, means for electrostatically charging a copy sheet having a photosensitive surface, means for exposing said copy sheet to an image of an original to be reproduced, means for feeding said copy sheet and said original from initially spaced, substantially vertical positions in synchronism through the machine, an optical system for scanning said original during the movement thereof and subjecting said copy sheet to exposure, means for developing the latent electrostatic image on said copy sheet subsequent to exposure, guide members for said original forming a substantially vertical, downwardly directed original travelling path, said charging means and said exposing means being likewise arranged along a mainly vertical, downwardly directed copy sheet travelling path.

It has been found that such a construction offers a surprising number of advantages. As a result of the fact that the original and the copy sheet are vertically arranged, the force of gravity may be utilized for obtain ing the necessary detection of the original and the copy sheet in the initial positions. Thus, the necessity of introducing two sheets into the machine at the same time in order to allow forwarding rollers to catch said sheets simultaneously is avoided. The original and the copy sheet can be forwarded individually to the initial positions in which they are upright and ready for being caught simultaneously by forwarding rollers.

The operation of an upright machine appears to be simpler and more convenient than the operation of a horizontal machine due to the fact that it is more convenient to move human arms vertically than horizontally.

Furthermore, the demands on space are much smaller in case of an upright machine, whether it is placed on a table or suspended on a vertical surface, e.g., a wall. Suspension on a wall is, in particular, ad vantageous. In many offices, in which the need to save space has prevented the installation of an electrophotographic copying machine, sufficient space will be available on a wall for suspending a machine constructed in accordance with the invention. The mounting on the wall may be carried out by means of a fixed fitting, onto which the machine can be hooked, if desired, at different heights, so that the machine is adjustable to an ergologically correct height for the user in question.

In addition, an upright machine offers considerable advantages with respect to the possibilities of servicing. The casing of the machine may be bipartite, the two parts thereof being pivotably connected along a vertical axis, whereby the machine may be opened in a manner like a wall cabinet with the difference, however, that the part of the casing which is pivoted outwardly from the wall comprises essential component parts of the machine. For example, it might be advantageous to align the separating plane with a substantially vertical portion of the path of the copy sheet in order to obtain a ready accessibility for removing a copy sheet, which has possibly become damaged.

BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention is explained in greater detail with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of an embodiment of an electrophotographic copying machine in accordance with the invention constructed for being suspended on a wall;

FIG. 2 is a side view of the machine shown in FIG. I, one side wall of the casing being removed for illustrating the arrangement of internal parts of the machine;

FIG. 3 is a perspective view of another embodiment of a copying machine in accordance with the invention, in the top of which a supply magazine of copy sheets is inserted;

FIG. 4 shows a box-shaped magazine for copy sheets for use in the machine shown in FIG. 3.

DETAILED DESCRIPTION FIG. I shows an embodiment of an lectrophotographic copying machine in accordance with the invention. in which the rear wall 1 of the casing of the machine is provided with holes for suspending the machine directly on a wall by means of fittings secured thereto, one of said holes being shown in the figure at 2. In order to make it possible to change the height at which the machine is suspended, the rear wall 1 may be provided with various sets of suspension holes corresponding to the hole 2, such holes being, however, not shown on the drawing. In order to provide access to the interior of the machine the rear wall 1 is connected with the remaining part of the casing by means of hinges, not shown, along one vertical side edge 3 and is provided at the opposite side edge with an elongated side member 4 having a number of holes of which only one is shown in the figure at 5, said holes serving to receive locking members, not shown, which are mounted at the edge of the one side wall 6 of the casing facing the side member, said locking members being actuable for opening the casing by means of a handle 7.

At the front side of the casing shown, a narrow, vertical duct for the insertion of an original to be copied in the machine is formed between the front plate 8 of the machine and a guiding plate 9 arranged parallel thereto. The guiding plate 9 which may be of a transparent material, for example plexiglass, has in the upper portion thereof a U-shaped cutout, by means of which it is possible to correct the insertion of the original into the duct.

In the lower portion of the front side of the casing two ejection openings 11 and 12 are provided for ejecting the original and the copy reproduced therefrom, respectively, from the machine. In the embodiment shown in FIGv l which is constructed to be suspended on a wall, a downwardly sloping tray I3 for collecting copies is arranged in connection with the copy ejection opening 12.

As shown in FIG. 2, the guiding plate 9 is secured, at the lower edge thereof, to a screening plate I4 for the devices serving to control the vertical downwards movement of the original during the copying process, said screening plate being pivotably mounted by means ofa hinge 15 at the one side edge. Thus, by opening the screening plate I4 and the guiding plate 9, easy access to the entire travelling path of the original inside the machine may be obtained.

At one side of the front wall of the casing, a control panel 16 is mounted, comprising, inter alia, a main switch I7, a band-wheel 18 for adjusting the luminous intensity during the exposure, a start-stop switch I9 and members 20 and 21 serving for the supply and control of toner liquid.

In the front portion of the top wall of the casing a pivotable cover 22 is provided, by the opening of which a stack of photo-sensitive copy sheets can be inserted and placed in a suitable holder inside the machine.

The detailed construction of the embodiment shown of the copying machine according to the invention is illustrated in FIG. 2, which shows the relative arrangement of the devices serving to feed the original and the photo-sensitive copy sheet, as well as the processing units necessary for charging, exposing, developing and drying the copy sheet, whereas a motor and associated transmission devices for driving the machine and further accessories such as a fan etc. are omitted, since these devices may be of a conventional design and are not important to the understanding of the invention.

As already mentioned, the insertion of an original into the machine takes place through a vertical duct 10 defined by the front plate 8 of the machine and a guid ing plate 9 arranged at a small distance therefrom. At the lower end of the duct 10, two feeding rollers 23 and 24 are mounted with horizontal axes, of which the roller 24 is driven by the motor of the machine through a suitable transmission device, not shown. In the inoperative state of the machine, i.e. in the absence of an original, the roller 23 is situated a small distance from the roller 24, so that an original may pass freely between the two rollers, whereas said roller 23 in the presence of an original can be pressed against said original and the roller 24 by means of coupling members, not shown, which may be of a design known per se, and which are actuated by means of the start-stop switch 19 shown in FIG. 1, said coupling members keeping the rollers pressed together in a period corresponding, for example, to the duration of the exposure of an original. The presence of the original is detected by means of stop members, which are arranged, as shown in FIG. 2 at 25, immediately below the rollers 23 and 24 and in alignment with the spacing therebetween, said stop members being constructed in a way so as to be retractable from the travelling path of the original subsequent to the coupling together of the rollers. Due to the fact that said stop members are each arranged at a small distance from one end of the feeding rollers 23 and 24 and offer together an abutment line for the front edge, passing between said rollers, of an original inserted through the duct 10, a well-defined initial position for the further movement of the original is thereby determined and a considerable degree of security against an oblique insertion of the original is obtained.

During the transport from the pair of rollers 23, 24 to a pair of rollers 29, 30, the original initially passes a transparent glass plate 26, a portion of which constitutes a window, through which the moving original is scanned by the optical system of the copying machine, which will be explained in greater detail in the following. During this movement the original is pressed flatly against the glass plate 26 by means of a pressure plate 27, which is connected by means of a spring 28 to the above-mentioned screening plate 14.

Immediately below the glass plate 26 and the pressure plate 27 two horizontal feeding rollers 29 and 30 are mounted with control the further movement of the original towards the ejection opening 11 after the scanning.

In order to provide access to the entire travelling path in case of jamming of an original, the rollers 23 and 29 may as shown be mounted on the screening plate 14.

In the embodiment shown of the copying machine according to the invention, the photo-sensitive copy sheets are placed in a holder for a stack of such sheets. Said copy paper holder is arranged completely inside the casing of the machine and comprises a plate 31 sloping downwards from the upper edge of the front plate 8 of the machine and forming a small angle of, for example, l0 to said front plate. The plate 31 has in the lower end thereof a rim 32 bent perpendicularly relative to the plate and a certain distance above said rim, an end plate for the copy paper holder is secured to the plate 31, for example, by spot welding, said end plate having the form of a U-shaped metal bar 33 extending transversely across the plate 31, the outer limb of said bar sloping downwards and forming a guiding plate for the movement of a sheet derived from the stack of sheets. At the ends of the U-shaped bar 33, small plateshaped members 34 are secured thereto, said members forming so-called edge separators, by means of which photo-sensitive sheets can be drawn individually from the stack of sheets in the copy paper holder. The stack of sheets in the holder is resting on a plate 35 having side rims bent perpendicularly relative thereto, as shown at 35a, said 35 being connected pivotably, at the upper end thereof, with the upper end of the plate 31 and being connected, in the lower end, with the plate 31 by means of a spring 35b pressing the plate 35 and the stack of sheets arranged thereon against the edge separators 34. When drawing a copy sheet, a downwardly directed movement is imparted to the uppermost sheet of the stack, the edge of said sheet jumping thereby over the edge separators and being moved by means of the guiding plate formed by the U-shaped bar 33 and a further guiding plate 36 connected to the rear wall 1 in a downwards direction towards two horizontal feeding rollers 37 and 38 which are mounted immediately below the edge separators, the roller 38 thereof being driven by the motor of the machine. In the inoperative state of the machine, i.e., in the absence of a copy sheet between the feeding rollers, the roller 37 is situated a small distance from the roller 38 so that a sheet can pass freely between said rollers, while in presence of a sheet, the roller 37 is pressed by means of coupling members, not shown, against said sheet and the roller 38 in the same manner as mentioned above for the roller 23 relative to the roller 24, said coupling members keeping the rollers pressed together for a suitable period subsequent to actuation. In the same man ner as in case of the rollers 23 and 24, stop members serving to detect the presence of a copy sheet, one of which members is shown in FIG. 2 at 39, are mounted immediately below the rollers 37 and 38. The construction of said stop members, which determine a welldefined initial position for the forwarding of the sheet,

is the same as described in the foregoing for the stop members associated with the rollers 23 and 24.

Subsequent to the coupling together of the rollers 37 and 38, the copy sheet is moved downwards by means of said rollers into a bipartite corona unit 40 in which the sensitive surface of the sheet is electrostatically charged, in a manner know per se, whereupon the sheet is moved into the spacing between two transparent glass plates 41 and 42, where the sheet is exposed during continued movement to the image of the original passing the glass plate 26, said image being formed by means of the optical system of the copying machine, the movement of the copy sheet being controlled in synchronism with the movement of the original by means of suitable transmission devices in the copying machine. Subsequent to the passage between the glass plates 41 and 42, the front edge of the sheet is caught by two horizontal feeding rollers 43 and 44 mounted immediately below said glass plates and the sheet is moved by means of said rollers into the developing unit 45 of the copying machine, which in a known manner comprises a bath 46 of a developing liquid as well as a device 47 for supplying toner liquid. The developing unit 45 is constructed in such a way that the sheet, when moving into said unit, is deflected in a horizontal direction. At the outlet of the developing unit 45 the copy, now developed, is caught by two horizontal feeding rollers 48 and 49 which, in addition to forwarding the copy to a drying unit 50, wipe of excessive de veloping liquid from the copy sheet. Subsequent to the passage through the drying unit 50, the detailed construction of which is not shown in FIG. 2, the finished copy is ejected through the ejection opening 12 in the front side of the machine by means of two horizontal feeding rollers 51 and 52.

In order to provide access to the travelling path of the copy sheet in case of the jamming of a sheet in the ma chine, the feeding rollers 37 and 43, one part of the corona unit 40 and the glass plate 42 are mounted by suitable means on the rear wall 1 so that the part of the travelling path extending between the sheet holder and the developing unit 45 is accessible by opening the machine as shown in FIG. 1.

In the embodiment shown of the copying machine according to the invention, the scanning of the original is carried out by means of a light source 53 in the form of, for example, a halogene lamp with an associated reflector 54 which may, as shown, be formed by a metal plate provided with a reflecting coating on the inner surface, a socket for the lamp 53 being secured to said metal plate.

As previously mentioned, only part of the glass plate 26 is utilized as a window for the scanning of the original, the upper part of the glass plate being covered on the inner side by a plate 55 of an opaque material. This measure serves to achieve in a simple manner a correct synchronism between the movements of the original and the photo-sensitive sheet since, as a result hereof, the distance between the initial position for the movement of the original and the upper limit of the scanning window, determined by the lower edge of the plate 55, may be equal to the distance brought about between the initial position for the movement of the copy sheet and the upper end of the spacing between the two glass plates 41 and 42 due to the presence of the corona unit 40. However, said measure is not in any way a precondition for putting the invention into practice, as synchronism between the original and the copy sheet may also be obtained by other measures. e.g., by means of a short time delay between the start of movement of the copy sheet and the original, respectively.

The reflector 54 with the associated light source 53 is mounted in such a way relative to the scanning win dow in the glass plate 26 that the optical axis of said reflector intersects the window in the center point thereof. The image of the original passing the scanning window is reflected by means of a plane mirror 56 towards a reflecting optical device comprising a plane mirror 57 and two lenses 58 and 59 forming one half part of a symmetrical objective. Said optical device is mounted in a holder 60 inserted in a suitable opening cut out in a plate 61, which is rigidly connected, for example, by spot welding to the front plate 8 of the copying machine and to the plate 31 of the copy paper holder. The image is reflected from said optical device towards a plane mirror 62 and is further reflected by the latter mirror in the direction towards the photo sensitive sheet passing between the glass plates 41 and 42. In order to prevent light from the light source 53 from reaching the photo-sensitive sheet directly, a substantially upright partition 63 is interposed between the plane mirrors 56 and 62.

The exposure in the copying machine is controllable by adjusting the luminous intensity by means of a dia phragm in form of a metal plate 64 mounted on a shaft 65 which is turnable by means of the hand-wheel 18 in the control panel 16 on the front side of the machine, as shown in FIG. I.

In order to obtain synchronism between the move ments of the original and the copy sheet in the copying machine, it will be necessary that all pairs of feeding rollers are driven at the same circumferential speed. It is not illustrated in the drawings how this is achieved. However, the said condition may be fulfilled in a known manner by driving continuously one roller of each pair of rollers by means of the motor of the machine through a common, endless drive belt which may be provided, in order to reduce play and friction, with teeth and may mesh with gears mounted on the roller shafts.

For the purpose of utilizing various sizes of original and photosensitive paper in the copying machine, lateral guides for two corresponding side edges. one of the original and one of the copy sheet, may be provided in connection with the guides for the original and the copy sheet, respectively. In case of the photo-sensitive sheet, such a guide may be constituted by the side rim 35a of the plate 35, while a corresponding vertical lateral guide may be provided in the insertion duct 10, as shown in a dotted line at 66 in FIG. 2.

FIG. 3 shows a view, corresponding substantially to that of FIG. 1, of another embodiment of an electrophotographic copying machine according to the invention, in which a considerable reduction of the height of the machine has been obtained as a result of a different design of the holder for the photo-sensitive copy paper. The reference numerals used in FIG. 3 correspond to those in FIG. 1. The embodiment shown in FIG. 3 is a machine intended for using copy paper which is supplied in box-shaped magazines as shown at 67 in FIGS. 3 and 4, said magazines being designed so that the magazine itself if used as a holder for the copy paper, as one end face 68 and a portion 69 of one large surface thereof can be torn off, whereupon the entire magazine may be inserted into the copying machine through a slit 70 in the cover 22 in the top wall of the casing in such a manner that the portion 71 of the magazine, not torn off, protrudes above the casing of the machine, As a result of this design, a considerable reduction in the height of the machine may, as mentioned, be obtained, the height being now mainly determined by the dis tances necessary between the members of the optical system of the machine, as shown in FIG. 2.

From the foregoing it will appear that an electrophotographic copying machine in accordance with the invention offers a very compact construction of such a machine, as a result of which considerable advantages in connection with shipment as well as installation of the machine are obtained, due to the reduced demands on space. Furthermore, due to the upright configuration an advantageous arrangement of the individual component parts in the interior of the machine is obtained and the risk of an oblique insertion of the original into the machine is materially reduced.

The embodiments shown in the drawings and described hereinbefore should in no way be considered limiting for the invention, since many modifications relative to said embodiments will be possible within the scope of the invention.

What I claim is:

l. A vertical electrophotographic copying machine comprising a vertically extending casing, means in the upper portion of the casing for receiving a stack of copy sheets, means for electrostatically charging a copy sheet having a photosensitive surface, means for feeding said copy sheet and said original from the upper portion of the casing in initially spaced positions in synchronism through the machine to respective ejection openings in the lower portion of said casing, a first substantially vertical transparent member for receiving said original as it passes between the upper portion of said casing and its respective ejection opening, a second transparent member positioned at an acute angle to said first transparent member for receiving said copy sheet as it passes between the upper portion of said casing and its respective ejection opening, an optical system for scanning said original during the movement thereof as it passes said first transparent member and subjecting said copy sheet to exposure as it passes said second transparent member, means to developing the latent electrostatic image on said copy sheet subsequent to exposure, guide means for said original forming a substantially vertical, downwardly directed original travelling path to its ejection opening in the lower portion of said casing, said charging means and said exposing means being likewise arranged along a mainly vertical, downwardly directed copy sheet travelling path, at least one stop member in the path of said original determining the intial position of said original, at least one stop member in the path of said copy sheet, said original and copy sheet being positioned in said original positions by gravity, and means for retracting said stop members from said paths, when the original and the copy sheet, respectively, have been positioned in said initial positions.

2. An electrophotographic copying machine comprising a casing, means for electrostatically charging a copy sheet having a photosensitive surface, means for exposing said copy sheet to an image of an original to be reproduced, means for feeding said copy sheet and said original from initially spaced, substantially vertical arranged along a mainly vertical, downwardly directed copy sheet travelling path at least one retractable stop member in the path of said copy sheet, means for detecting a copy sheet in contact with said stop member, a pair of cooperating copy sheet feeding rollers and means for actuating said rollers and retracting said stop member upon detection of a copy sheet. 

1. A vertical electrophotographic copying machine comprising a vertically extending casing, means in the upper portion of the casing for receiving a stack of copy sheets, means for electrostatically charging a copy sheet having a photosensitive surface, means for feeding said copy sheet and said original from the upper portion of the casing in initially spaced positions in synchronism through the machine to respective ejection openings in the lower portion of said casing, a first substantially vertical transparent member for receiving said original as it passes between the upper portion of said casing and its respective ejection opening, a second transparent member positioned at an acute angle to said first transparent member for receiving said copy sheet as it passes between the upper portion of said casing and its respective ejection opening, an optical system for scanning said original during the movement thereof as it passes said first transparent member and subjecting said copy sheet to exposure as it passes said second transparent member, means to developing the latent electrostatic image on said copy sheet subsequent to exposure, guide means for said original forming a substantially vertical, downwardly directed original travellinG path to its ejection opening in the lower portion of said casing, said charging means and said exposing means being likewise arranged along a mainly vertical, downwardly directed copy sheet travelling path, at least one stop member in the path of said original determining the intial position of said original, at least one stop member in the path of said copy sheet, said original and copy sheet being positioned in said original positions by gravity, and means for retracting said stop members from said paths, when the original and the copy sheet, respectively, have been positioned in said initial positions.
 2. An electrophotographic copying machine comprising a casing, means for electrostatically charging a copy sheet having a photosensitive surface, means for exposing said copy sheet to an image of an original to be reproduced, means for feeding said copy sheet and said original from initially spaced, substantially vertical positions in synchronism through the machine, an optical system for scanning said original during the movement thereof and subjecting said copy sheet to exposure, means for developing the latent electrostatic image on said copy sheet subsequent to exposure, guide members for said original forming a substantially vertical, downwardly directed original travelling path, said charging means and said exposing means being likewise arranged along a mainly vertical, downwardly directed copy sheet travelling path, at least one retractable stop member in the path of said copy sheet, means for detecting a copy sheet in contact with said stop member, a pair of cooperating copy sheet feeding rollers and means for actuating said rollers and retracting said stop member upon detection of a copy sheet. 